Update note about network isolation support

Signed-off-by: Dan Barr <[email protected]>

Author: danbarr

docs/toolhive/guides-ui/network-isolation.mdx

@@ -24,8 +24,9 @@ protocols are not supported.
 
 ## Enabling network isolation
 
-Currently, network isolation is available for MCP servers installed from the
-ToolHive registry.
+Network isolation is available for local MCP servers installed from the registry
+or custom servers. It is not available for remote MCP servers, which are hosted
+and outside of ToolHive.
 
 During the MCP server installation, select the **Network isolation** tab in the
 configuration form. Click the toggle to enable it.